The biology of our oceans is dominated by microbes too small to be seen with the naked eye. One such group, phytoplankton, help remove the greenhouse gas carbon dioxide from the atmosphere, turning it into food for all other life in the sea. They also generate about half the oxygen humans breathe. Life on our planet depends on the activities of these phytoplankton communities. However, marine waters, including these organisms, are being severely affected by human activities, which in turn impact our entire planet. Professor Armbrust discusses the connection between the health of our oceans and human health. From the Series:Science Forum